It has been shown previously that the frequent sampling of plasma over twenty-four hours is a research tool that provides important insights into the circadian variations of gonadotropins and melatonin during puberty and hGH, cortisol, prolactin during life. Using this procedure, the following groups of patients are being studied to furhter understand disorders of puberty and regulation of hypothalamic-pituitary axis indisease and normal states. 1. All subjects with disorders of puberty (precocious, delayed, microphallus, Turner syndrome, androgen insensitivity). 2. Patients with juvenile onset diabetes mellitus - to determine the effect of diabetes on normal maturation. 3. Patients with juvenile rheumatoid arthritis - to determine the effect of J.R.A. on growth and development. 4. Patients with growth hormone deficiency or excess. 5. Patients with Cushing's disease and congenital adrenal hyperplasia - to delineate further the hypothalamic-pituitary-adrenal interaction.